The present invention relates to a compound speaker for a portable communication device such as a portable telephone.
The portable telephone has a speaker for converting a call signal into a sound and a receiver for connecting a sound signal into a sound. If the speaker and the receiver are disposed at different positions in the telephone, it is difficult to compose the telephone in a miniature. In order to miniaturize the portable telephone, the compound speaker is provided.
FIG. 13 is a plan view of a conventional compound speaker, FIG. 14 is a sectional view taken along a line XIVxe2x80x94XIV of FIG. 13, FIG. 15 is an underside view, and FIG. 16 is a sectional view taken along a line XVIxe2x80x94XVI of FIG. 15.
In a case 1 made of synthetic resin, there is provided a yoke 2 made of a magnetic material.
The yoke 2 comprises a flange 2a formed on an upper periphery of a cylindrical portion 2b having a bottom 2c. An annular first magnet 3 is secured to the underside of the flange 2a, and a second magnet 8 having disc shape is secured to the bottom 2c of the yoke 2. An annular first top plate 4 made of a magnetic material is secured to the underside of the first magnet 3, and a second top plate 9 having a disc shape is secured to the upper surface of the second magnet 8.
A first diaphragm 6 is secured to the underside of the case 1, and a second diaphragm 11 is secured to the upper surface of the case 1. A first voice coil 5 and a second voice coil 10 are secured to inside surfaces of the first and second diaphragms 6 and 11, respectively. The first diaphragm 6 and the first voice coil 5 compose a first sound production device as a speaker, and the second diaphragm 11 and the second voice coil 10 compose a second sound production device as a receiver. Protectors 7 and 12 are secured to the underside and upper surface of the case 1 for protecting the diaphragms 6 and 11.
There are formed two magnetic gaps. One of the magnetic gaps is a magnetic gap between the periphery of the cylindrical portion 2b of the yoke 2 and the inside wall of the top plate 4. A magnetic field is formed in the magnetic gap based on the magnetic force of the first magnet 3.
The other is a magnetic gap between the inside wall of the cylindrical portion 2b and the periphery of the top plate 9. A magnetic field is formed in the gap by the magnetic force of the second magnet 8.
When a signal current is applied to the voice coil 5 or 10, the diaphragm 6 or 11 is vibrated to generate sounds.
There is formed sound discharge holes 7a formed in the protector 7, sound discharge holes 12a in the protector 12. Furthermore, there are formed vents 1a behind the diaphragm 6 and vents 1b beside the diaphragm 11.
FIG. 17 is a sectional side view showing the conventional compound speaker mounted in a case of a portable telephone, FIG. 18 is a sectional plan view of the portable telephone. A circuit substrate 23 is securely mounted in a case 22 by supporting pillars 22c. The circuit substrate 23 has a large recess 23a. The compound speaker 21 is disposed in the recess 23a and securely mounted in the case 22 by posts 22b. The protectors 7 and 12 are held by resilient members 24 and 25 such as rubber. Terminal electrodes 13 of the compound speaker 21 are connected to a circuit on the circuit substrate 23 by flexible print plates 26. There is provided a liquid crystal display 29 in the case 22.
FIG. 19 is a sectional side view showing another method for mounting the speaker in the case, and FIG. 20 is a sectional plan view.
As shown in FIG. 19, a lead wire 14 is drawn from each terminal electrode 13. Further, the lead wire 14 is connected to the circuit substrate 23.
In the conventional compound speaker, sound discharge holes 7a and 12a are provided on the upper side and the lower side of the speaker as shown in FIG. 14. Therefore, the speaker can not be directly mounted on the circuit substrate 23. Consequently, as shown in FIGS. 18 and 20, the large recess 23a is formed in the substrate 23, the substrate must be supported at an intermediate height, and the speaker 21 must be disposed in the recess. Furthermore, sound discharge holes 28 must be formed in both sides of the case 22. Therefore, a complicated supporting structure is necessary, and the appearance of the portable telephone decreases because of the sound discharge holes.
An object of the present invention is to provide a compound speaker which may directly be mounted on a circuit substrate.
According to the present invention, there is provided a compound speaker comprising a case having a peripheral side wall, a first sound production device provided in the case, a second sound production device provided in the case, a first sound discharge hole formed in the case for discharging sounds produced by the first sound production device, a second sound discharge hole formed in the case for discharging sounds produced by the second sound production device, at least one of the first and second sound discharge holes being formed in the peripheral side wall so as to discharge sounds in a lateral direction.
The discharge hole provided in the peripheral side wall is provided in a sound discharge pipe projected from the side wall.
The first and second sound discharge holes are formed in protectors provided for protecting the first and second sound production devices.